Manufacture of filaments from cellulose solutions.



Patented Oct. 7, I902.

E. THIELE.

, MANUFACTUBE 0F FILAMENTS FROM CELLULOSE SOLUTIONS.

(Application filed Apr. 1, 1902.)

(No Model.)

rm: uonms PETERS so. wnoro-umow. WASHING UNrTED STATES PATENT OFFICE.

EDMUND THIELE, OF BARMEN, GERMANY.

MANUFACTURE OF FILAMENTS FROM CELLULOSE SOLUTIONS,

SPECIFICATION formingpart of Letters Patent No. 710,819, dated October'7, 1902.

Application filed April 1, 1902. Serial No. 100,981. (No specimens.)

To all whom it may concern:

Be it known that I, EDMUND THIELE, a subject of the Emperor of Germany,residing at Barmen, Germany, have invented certain new and usefulImprovements in the Man u factu re of Filaments from CelluloseSolutions, of which the following is a description.

The manufacture of filaments from cellulose solutions has heretoforebeen effected by causing the solutions to be forced by pressure throughcapillary tubes into a medium which effects the decomposition of thesolution and produces a solidification of the cellulose, such mediumbeing generally a liquid. The diameter of the filament, as also itsdegree of fineness, is in this case mainly determined by the internaldiameter of the dischargeopening. The solidity of the filament producedis mainly dependent upon the content of cellulose in the solutionsemployed that is to say, upon the viscousness of the cellulose solution.The relation between the viscousness of the solution and the degree offineness of the capillary tubes is, however, confined between certainlimits, as the internal friction of the cellulose solution in thecapillary tubes becomes the greater the more viscous the solution is,whereby the issue of the solution is greatly impeded. On this accountthe cellulose solution is generally forced through the capillary tubesunder a more or less high pressure. For example,\Vyss-Naef Z)ciifschrzfl fi'lr angewcmdte Chcmie, 1899, Seite 32) mentions in hisarticle on the Chardonnet process a pressure of from forty to fiftyatmospheres with a capillary opening of 0.08 millimeters. There is afurther disadvantage connected with the very small diameters of thecapillary tubes for the production of fine filaments. The cellulose mustbe very carefully filtered before being forced through the tubes, whichin the case of viscous solutions can only be effected by very highpressure; but even then the clogging of the very fine discharge-openingsfrequently takes place, and although the capillary tubes can be readilychanged there will always be caused a loss of material and of time.These disadvantages have been partially obviated in the employment ofnitrocellulose (collodion) for the production of sill lil e filaments byLehner, who effects the formation of the filament in such manner that acomparatively thick filament issuing from a not very fine opening, suchas one-fourth or one-eighth millimeter, is reduced to a fine conditionby drawing it out to a greater or less extent. Such a process has,however, not heretofore been employed with the aqueous solutions ofcellulosesuch as am moniacal copper-oxid solution, chlorid-of-zincsolution, viscose solutionthe particular value of which for themanufacture of silk-like filaments has been recently acknowledged. Thisis easily explained. The formation of the filament from thenitrocellulose solutions is effected by the removal of the solvent, andtherefore quite gradually. \Vith the aqueous solutions of cellulose thesolution is, on the other hand, decomposed, the cellulose being at onceseparated in a solid form. It is still more or less elastic; but itcannot be permanently altered in its form. It could, therefore, not beexpected to be able to produce the filaments from cellulose, as in thecase of nitrocellulose, by drawing out thicker filaments.

I have made the important discovery that strongly concentrated cellulosesolutions have in the above respect special properties. These solutionscontain such quantities of cellulose and have such a consistency that bysimply drawing out the mass in the open air solid filaments are at onceproduced. The formation of the filaments is due to the fact that from athin layer of the concentrated solution the air takes away so much wateror ammonia that a superficial solidification of the solution iseffected; but the formation of the filaments is not effected in thedesired uniform manner. Better results are obtained if the cellulosesolution is caused to issue through capillary tubes of about one-halfmillimeter diameter into warm air heated by steam or otherwise; but theproduction of the filaments by drawing out the concentrated cellulosesolutions is best effected if the solution is caused to flow throughcomparatively large openings, such as one-half to onefifth millimeterdiameter, into certain liquids which slowly separate or precipitate thecellulose. For cellulose solutions rich in ammonia, for example, it hasbeen proved to be advantageous for this purpose to use heated water andvolatile liquids-such as acetic ether and other ethers, benzol,chloroform carbon tetrachlorid, and similar liquidswhich are notentirely insoluble in water. Such liquids which have not of themselves aprecipi rating action can be employed with the addition of othersubstances for drawing out the cellulose solutionssuch, for instance, asoils and fats, with the addition of olein; ligroin, with addition ofether, alcohol, and similar substances; water, with the addition ofalcohol, ether, glycerin, salts, and acids.

With concentrated cellulose solutions that are poor in ammonia some ofthe liquids namedsuch as, for instance, warm water and diluteacids-still have a too strongly precipitating property and may thereforegive rise to a fracture of the filaments when these are being drawn outrapidly. In such cases it is of advantage to use as aslowly-precipitating liquid pure cold water of from 10 to 20 centigrade,and if this should still act too rapidly with the addition of a smallquantity of alkaliin particular ammonia, whereby the removal of ammoniaand copper, which effects the precipitation of the cellulose, will beretarded, and the greater liquidity of the concentrated cellulosesolution will be prevented which occurs at higher temperatures. At thesame time these precipitants enable a saving of ammonia to be effectedand also the repeated use of the precipitating liquid, which graduallybecomes richer in ammonia. The number of the available precipitants is,however, by no means exhausted by the above examples. It is a necessarycondition for the utility of the said precipitants that they shall actwith a slowly-precipitating action upon the concentrated cellulosesolutions, and consequently produce the formation of the solid filamentonly after a certain duration of the precipitating action. Thus liquids,such as strong acid solutions, which at once effect the decomposition ofthe cellulose solutions with separation of the cellulose or which efiectthe immediate coagulation of the cellulose solutions are not useful forthe process in question. Also those liquids which do not take up eitherwater or ammonia from the cellulose solutions cannot be used for thedrawing out of the filaments.

The drawing out of the filaments in the slowly-acting precipitatingmedium can be effected by any suitable mechanical device such, forinstance, as a rapidly revolving roller. Gravity may, however, alsobeutilized for drawing out the filaments within the slowly-actin gprecipitating medium-namel y, while on one hand the filaments rapidlylose their contents of metal, such as copper and zinc, when subjected toa rapidly-acting precipitating medium and then on account of the lowspecific gravity of the cellulose sink only slowly in the liquid, on theother hand when using a slowly-acting precipitating medium the filamentsrich in metals, and consequently of high specific gravity, will exercisea strong downward pull, and therefore if the height through which theydescend is sufficient they will produce a reduction of the section ofthe higher part of the filament in drawing it out. This mode ofoperating constitutes not only a considerable simplification of theprocess, as special drawing-out devices are entirely dispensed with, butit also produces a very uniform filament, as the gravity of the filamentunder normal working will constitute an exceedingly uniform drawing-outpower and will not cause a fracture of the filament in the case of anydisturbance occurring, as would be the case if an independent mechanicalstretching device were employed.

The height through which the filament should descend in theslowly-acting precipitating medium will depend upon the degree of theaction of the latter, upon the diameter of the discharge-opening, uponthe concentration of the cellulose solution, and the desired fineness offilament. The drawing out of the filament in the slowly-precipitatingmedium can be aided by imparting to the precipitating liquid aconsiderable motion in the direction of the issue of the filament, so asto cause it to draw the formed filament along with it. v

In practically carrying out the process it is of advantage to cause theslowly-acting and rapidly-acting precipitating liquids to operate insuperposed layers upon the filament or arrange them in communicatingreceptacles in such manner that the issuing filament first passesthrough the slowly-acting precipitant, where it is drawn out, and isthen caused to pass through the rapidly-acting precipitant for thepurpose of completing the requisite decomposition without being subjectto further manipulations while in a very sensitive condition of itsincomplete decomposition.

If several discharge-openings are placed closely side by side, thedrawn-out filaments will on issuing from the bath unite on account oftheir attraction of cohesion for forming thicker bundles of filamentsthat can be more readily manipulated, but that will not stick together,such uniting of the filaments being elfected without requiring specialmeans for the purpose, as is requisite in the known processes. In thiscase should one of the filaments break the fractured part will becarried along by adhesion to the other filaments without causing anyinterruption of the operation.

I will now describe, by way of example, various modes of practicallycarrying my said invention into effect.

1. For the cellulose solution is taken a highly-concentrated ammoniacalcopper-oxid solution of cellulose, which is forced without materialpressure from a raised reservoir through several discharge-openings inthe side wall of a tank. The discharge-orifices have a diameter of fromone-half to one-fifth millimeter and may be of any desiredconfiguration; but the surface surrounding the orifice should be assmall as practicable in order to prevent the adhesion of the cellulosesolution as far as possible. Thus thick glass tubes should be avoided.Thetank, which is about one meter long, contains ether as theprecipitating liquid. The drops of the cellulose solution hanging fromthe orifices of the tubes are simultaneously seized by a holding deviceand are led to a glass roller revolving in sulfuric acid outside thetank. The several filaments issuing from the precipitating liquids in amoist condition adhere to each other, so that no special means arerequired for leading them together in order to unite them. It is,however, of advantage to provide a suitable movable guide either i11-side oroutside the tank for leading the formed thread laterally to andfroover the roller.

2. The cellulose solution is worked in the same way as at Example 1; butthe dischargeorifices are so arranged as to be situated in a recess inthe bottom of the precipitati neg-tan k. By this means it is renderedpossible to maintain the precipitating liquid surrounding the dischargeopenings at a lower temperature than that of the liquid in the otherparts of the tank. Water is in this case used as the precipitatingliquid, the temperature of the lower strata being maintained at from 40to 50 ceutigrade and that of the upper strata at from 95 to 100. Thefilament is otherwise treated as above described.

3. The precipitating-tank referred to in Example 2 is employed and thetemperature of the water is maintained, respectively, at from 35 to 40and at from 50 to 55. The hotter upper stratum of water is covered witha layer of olein about one centimeter thick,which acts upon thecompletely drawn-out thread like an acid and effects also the removal ofall solid impurities that may float in the water, such as copperhydroxid, which is taken up by the layer of olein. The winding up of thefilament is effected in the manner above described upon a rollerrevolvingin sulfuric acid. The issue of the cellulose solution and thedrawing out thereof are effected in the above-mentioned liquids in anexceedingly uniform manner. As soon as the ratios between the speed ofrotation of the roller and that of the issue of the cellulose solutionis suitably adjusted no breaking of the filament will ocour. Thefilament is drawn out to a degree of fineness quite equal to that ofnatural silk,

thus greatly increasing its valuable property as regards elasticity, andconsequently its usefulness for the production of woven fabrics. It iscertainly not possible to produce filaments of equal fineness by meansof the methods heretofore employed of ejecting the cellulose solutionthrough fine orifices into liquids that immediately solidify thefilaments. A further essential advantage con sists in the convenientmode of forming the discharge-orifices,the prevention of any chokingthereof, and also of any breaking of the thread. This improved method ofmanufacture also allows of an exceedingly-rapid rate of production. Thespeed of formation of the filament is only limited by the degree ofadhesion of the filament to the surface of the precipitating liquid. Allthese advantages, which occur in the same way when forming filaments ofall concentrated cellulose solutions, afford the improved process aconsiderable practical value. The drawing out of the filaments in theslowly-acting precipitating liquid by the agency of their own gravitycan be effected by means of apparatus such as shown, by way of example,on the accom panying drawings.

4. In Figure 1 numerous filaments issue from the perforated rose-likeend of the tube a and are considerably extended by their own gravity inpassing down through the tube 1), filled with slowly-actingprecipitating liquid. They are then led through the narrowconnectingpassage into the tube d, which is filled with rapidly-actingprecipitating liquid, and after leaving 01 they are wound up in theusual way, scoured, and washed. The passage of the filaments isindicated by dotted lines on the drawings. The tubes 1) and d areprovided with supply and discharge pipes efg h for discharging theprecipitating liquids when they have been rendered inefficient afterlong use and replacing them with fresh liquids. For enabling the tubes bd to be cooled or heated, as may be required, they are surrounded byjackets 'i 7;, through which a cooling or heating fluid is made tocirculate.

5. In the arrangement at. Fig. 2 the filaments issue from the tubes Z Zand pass through the vessel m, filled with slowly-acting precipitatingliquid, into the vessel n, filled with the same liquid, and are wound upon the roller 0, and while on this they are successively treated withthe rapidly-acting precipitating liquid,with acid,and with water. Forstretching the issuing filaments in the tubem there is provided betweenthe tube on and tank n a fluidmotor q, operating as a propeller,whichdrives the liquid energetically in the direction of the issue of thefilaments through the tube m, and thereby draws out the comparativelythick filaments to any desired degree of fineness.

Having thus described my invention, the following is what I claim as newtherein and desire to secure by Letters Patent:

1. The process for the manufacture of filaments from cellulose solutionswherein an aqueous cellulose solution issues through comparatively largeorifices into a precipitating medium that acts only slowly upon theaqueous cellulose solution, said issuing solution being drawn out tofine filaments in such medium, substantially as described.

2. Process for the manufacture of filaments from cellulose solutionswherein the cellulose solution issues through comparatively largeorifices into a precipitating medium that acts only slowly upon thecellulose solution, said issuing solution being drawn out into finefilaments in such medium by the action of its own gravity, substantiallyas described.

3. Process for the manufacture of filaments from cellulose solutionswherein the cellulose solution issues through-comparatively largeorifices into a precipitating medium that acts only slowly upon thecellulose solution, said issuing solution being drawn out to finefilaments in such medium,after which it is subjected to the action of amore rapidly acting precipitating medium, both media touching each otherin such manner that the filament can pass from the slowly-actingprecipitant directly into the rapidly-acting precipitant, substantiallyas described.

4. Process for the manufacture of filaments from cellulosesolutionswherein the cellulose solution issues through comparatively largeorifices into a liquid-precipitating medium that acts only slowly uponthe cellulose solution, said issuing solution being drawn out to finefilaments in such medium, after which it is subject to the action of amore rapidly acting precipitating medium which either forms a stratumbelow the slowly-acting medium, or is contained in a receptaclecommunicating with the latter, substantially as described.

5. Process for the manufacture of filaments from cellulose solutionswherein the cellulose solution issues through comparatively largeorifices into a liquid -precipitating medium that acts only slowly uponthe cellulose solution, said issuing solution being drawn out to finefilaments in such medium, such drawing out being effected by imparting arapid motion to the precipitating liquid in the direction of issue ofthe filaments, substantially as described.

6. Process for the manufacture of filaments from cellulose solutionswherein the cellulose solution issues through-comparatively largeorifices into a precipitating medium that acts only slowly upon thecellulose solution, said issuing solution being drawn out into finefilaments in such medium by the action of its own gravity, such drawingout being aided by imparting a rapid motion to the precipitating liquidin the direction of issue of the filaments, substantially as described.

EDMUND TIIIELE.

\Vitnesses:

OTTO KONIG, J. A. RITTERSHAUS.

